Conventionally, as a display device usable for a display of a mobile terminal, a TV or the like, an organic EL (electroluminescence) display device including an organic EL element is known. An organic EL display device has advantages of emitting bright light, having superb viewing angle characteristics, and the like, and thus rapid development thereof is desired to provide a display device replacing a liquid crystal display device.
Usually, an organic EL display device includes a flattening film covering a thin film transistor and a light emitting element provided on the flattening film. For example, Japanese Laid-Open Patent Publication No. 2009-016231 and Japanese Laid-Open Patent Publication No. 2012-22787 discloses an organic EL display device including a pixel electrode provided on a flattening film containing an organic material, an inorganic insulating film exposing a part of a top surface of the pixel electrode, and an organic layer provided on the exposed part of the pixel electrode.